#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
char* my_strcpy(char* dest, char* src)
{
    char* ret = dest;
    while (*dest != '\0')
    {
        dest++;
    }
    while (*dest++ = *src++)
    {
        ;
    }
    return ret;
}
int main()
{
    char arr1[] = "hello ";
    my_strcpy(arr1, "world");
    printf("%s\n", arr1);
    return 0;
}